Electronic systems and circuits have made a significant contribution towards the advancement of modern society and are utilized in a number of applications to achieve advantageous results. Numerous electronic technologies such as digital computers, calculators, audio devices, video equipment, and telephone systems facilitate increased productivity and cost reduction in analyzing and communicating data, ideas and trends in most areas of business, science, education and entertainment. Often these advantageous results are achieved through the use of electronic components. To obtain desired performance results from electronic components it is usually critical for the components to operate reliably. Without reliable operation an electronic component usually does not perform properly and results are suspect.
The importance of information processed and communicated by modern electronic systems is increasing and can result in significant economic impact if the processing and communication operations are not reliable. Accurately establishing the reliability of increasingly complex and sophisticated electronic components and systems is difficult. For example, an almost insatiable desire for increased communication bandwidth and information processing capacity has led to a tremendous demand for advanced capabilities. However, even advanced electronic components usually have some probability of failure and the probability of failure typically increases as the components are used and operating conditions cause stress over time.
Traditionally, a reliability indication is estimated before a component is shipped and is typically based upon testing of a component simulating an anticipated “average condition”. For example, a Medium Time Between Failures (MTBF) value estimated before shipment is based upon “average condition” assumptions. However, the “average condition” assumptions do not usually provide an accurate representation of actual in field conditions for a particular use. When a component is shipped, control over operating conditions is lost and users (e.g., customers) typically expose the electronic components to a wide variety of operating conditions.
Operating conditions have a significant impact on reliability. There are a variety of environmental and operational stresses that can detrimentally impact failure rates and reliability. For example, typically the number of “operations” electronic components perform (e.g., transistors turning on and off as data traffic passes through a communications component), the higher the likelihood of a failure because the operations usually electrically stress the components. A high temperature environmental condition also contributes to stressing the components in a detrimental manner and increases the likelihood of a failure. As a component participates in greater operational activities and diverse environments, accurately establishing the reliability of network components becomes more difficult.
Inaccurate reliability values can have numerous detrimental impacts including diminished confidence in a component. Customers often treat the reliability of a component as an asset. Components with higher reliability usually do not adversely impact revenue generating operations as often as low reliability components and high reliability components typically do not result in repair or replacement expenses as often. Customers also sometimes utilize reliability values in maintenance decisions and inaccurate reliability values can adversely impact maintenance operations.
Reliability values are often utilized as a fundamental manufacturing and/or service parameter. The reliability values can be used to predict the number of components returned for service and/or repair and the support required to address the service and/or repair demand. For example, reliability values are often utilized to forecast the amount of “spare parts” inventory to manufacture and maintain for servicing and repair operations. Furthermore, when a component is returned for servicing or repair and a component failure is identified, attempts at factoring the failure in reliability estimates are sometimes made. However, the operational and environmental conditions are not usually tracked and impacts associated with the conditions are not included in attempts to factor the failure in future pre-shipment failure estimates. Traditional attempts at establishing reliability do not usually include actual field usage information and can result in erroneous assumptions on the quality of the system, statistical behavior and future predictions.